| With the deepening of western development strategy,the construction work in mountain areas process rapidly,a large number of high and steep slope appeared along with the highway construction.Given by the unique internal factors of topography,geomorphology,geology,climate,hydrology and lithology influence,rock fall had already brought a serious safety threat for the nearby residents and highway,which is triggered either by the exteranal factors of earthquake or human engineering activities.Currently,there are only a few researches focus on this special rock fall.Southwesten part of China present complex geological situation,multiple rock category,and significant mechanical differences.Studies should focus on the regional distributed special rock characteristic influence on the rock movement as well as its influence level.Currently,there are only a few researches pay their attension on the physical and mechanical engineering characteristics of regional distributed rock themselves,at the same time seldom mention the combination of rockfall body features and rockfall movement.Relying on the widely distributed phyllite rock in the construction areas in southwest part of China,phyllite shows mineral diversity and based on that,combined with weathering degree influence,the rockfall in the study area is classified upon these.After that,the physical and mechainical properties of the rock body itself are combined with the rock broken characteristics in the motion process.It was affected by multiple factors and belongs to nonlinear change law,which fractal theory is introduced here to try to use single fractal quantitative index to measure the whole features of rockfall body.On this basis,the combination of Newton's laws of motion,impulse discrete element method and the law of conservation of energy,the numerical simulation of multibody collision slope rockfall analysis method is put forward,which by means of the c + + programming language.Finally,the energy tracking method program compilation work is done in the Windows operating system,which achived the goal of using user-defined energy tracking method to analyze and calculate the slope rockfall problem.Relying on the scientific and technological demonstration project of the Guanggan highway,through field survey,laboratory tests,theoretical and numerical analysis,the characteristics of regional rock fall risk researches were studied.This purpose is implemented based on detail information of rock fall situation along the highway and through the rock classification,physical and mechanical properties,fragmentation properties,size distribution properties,movement form and combined with slope form and slope height.The main works were as follows:1.There is no certain definition for rockfalls in current academic analysis.We make a distinction among rockslides,collapse and dangerous rocks,treat rockfall as smaller collapse behavior,treat dangerous rocks as the material basis,which is the illstability of rockfall.The comprehensive study of the formation of rockfall and its type provide theotetical basis for rockfall study and anlyze the development of potential rockfall morphology and failure modes.2.Based on the survey of the highway construction,the micro mineral characteristics of the phyllite is explored and worked out a preliminary phyllite category from the perspective of mineral composition and microscopic distribution.The general conclusion about rock's category and weathering degree in terms of seasonal influence,size range,high risk probability is given,and combined with falling rock body movement forms and analytical methods as to provide theoretical basis for further numerical simulation analysis.3.The rockfall process is considered as the collisions between rock themselves or rock and slope.The impact test is selected to simulate the particle breakage features under the action of collision.By test analysis results,influence on seasonal rock fall,rockfall body size range,high-risk category and the weathering degree of rock fall body types,basis given rockfall body movement forms and analytical method as to provide theoretical basis for further numerical simulation analysis.4.The fractal theory is introduced into phyllite rockfall risk analysis,using random fuzzy linear regression method,considering randomness,fuzziness and uncertainty of rockfall body distribution.The fractal dimension is valued as a quantitative index,which helps comprehensive evaluate the distribution fractal properties of rock fall: determine the type of the relevant phyllite,weathering degree,slope height,the fractal dimension value impact effect on the change rule of the influence.The physical and mechanical properties of rockfall and block broken feature are expressed by the fractal dimension value and its comprehensive expression change rule,which provides a quantitative index and evaluation method for comprehensive evaluate the phyllite rockfall broken collision characteristics,given a convenient and visual quantitative indicators for rockfall evaluationg physical and mechanical properties on the other hand.5.Based on the impulse analysis method,the rockfall collision procesure is treated as the collision problems of discrete objects.Based on the angle of energy conservation,energy tracing method is used to solve three-dimensional collision between multiple non-convex objects optimization,finally carried out a effective theory for computing slope rockfall problems.It is discussed among impulse,energy tracking and friction factors,which are the key factors for the implementation of the method.A detail discussion is expressed due to the consideration of compression,recovery and separation of the three phases in the collision process.6.Based on energy tracking method,through relevant theories on slope rockfall numerical simulation of collision procedure,editor with c + + users' self-programming software based on Windows environment for the numerical simulation method,the geometric and physical modeling based on the site survey data is established and simulated,which is analyzed from the form of slope,slope angle,slope height,rockfall movement pattern,the size of the rockfall,rockfall particle distribution.The rockfall dangerous bottom maximum transverse distance and its changing pattern are measured as indicators to analyze the multiple rockfall affecting factors.7.The three-dimensional numerical rockfall analysis results could provide slope rockfall protection measure to the research area,which contain existing slope rockfall security threats,based on energy tracking method and field survey.Through the analysis results of reginal distributed phyllite rock,the rockfall body itself differences in engineering properties dramatically affects the rockfall motion.Based on the analysis results,it is necessary to do individualized studies about the special rockfall body itself and combined with rockfall movement characteristics,which provide a more accurate and effective evaluation method for rockfall hazards study. |
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